libceph: fix a use after free issue in osdmap_set_max_osd

If the state variable is krealloced successfully, map->osd_state will be
freed, once following two reallocation failed, and exit the function
without resetting map->osd_state, map->osd_state become a wild pointer.

fix it by resetting them after krealloc successfully.

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>

1 files changed, 16 insertions, 16 deletions

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index c547e46084d3..ec4d9e24dcf9 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -671,26 +671,26 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, int max)
         int i;
 
         state = krealloc(map->osd_state, max*sizeof(*state), GFP_NOFS);
+        if (!state)
+                return -ENOMEM;
+        map->osd_state = state;
+
         weight = krealloc(map->osd_weight, max*sizeof(*weight), GFP_NOFS);
-        addr = krealloc(map->osd_addr, max*sizeof(*addr), GFP_NOFS);
-        if (!state || !weight || !addr) {
-                kfree(state);
-                kfree(weight);
-                kfree(addr);
+        if (!weight)
+                return -ENOMEM;
+        map->osd_weight = weight;
 
+        addr = krealloc(map->osd_addr, max*sizeof(*addr), GFP_NOFS);
+        if (!addr)
                 return -ENOMEM;
-        }
+        map->osd_addr = addr;
 
         for (i = map->max_osd; i < max; i++) {
-                state[i] = 0;
-                weight[i] = CEPH_OSD_OUT;
-                memset(addr + i, 0, sizeof(*addr));
+                map->osd_state[i] = 0;
+                map->osd_weight[i] = CEPH_OSD_OUT;
+                memset(map->osd_addr + i, 0, sizeof(*map->osd_addr));
         }
 
-        map->osd_state = state;
-        map->osd_weight = weight;
-        map->osd_addr = addr;
-
         if (map->osd_primary_affinity) {
                 u32 *affinity;
 
@@ -698,11 +698,11 @@ static int osdmap_set_max_osd(struct ceph_osdmap *map, int max)
                                     max*sizeof(*affinity), GFP_NOFS);
                 if (!affinity)
                         return -ENOMEM;
+                map->osd_primary_affinity = affinity;
 
                 for (i = map->max_osd; i < max; i++)
-                        affinity[i] = CEPH_OSD_DEFAULT_PRIMARY_AFFINITY;
-
-                map->osd_primary_affinity = affinity;
+                        map->osd_primary_affinity[i] =
+                            CEPH_OSD_DEFAULT_PRIMARY_AFFINITY;
         }
 
         map->max_osd = max;